Film cassette with flanged film spool

ABSTRACT

In a film cassette, a flange has a central opening into which a spool core for a filmstrip extends to allow rotation of the spool core relative to the flange in film unwinding and film winding directions. According to the invention, a locking pawl supported on a resilient cantilever of the flange biases the locking pawl into the central opening to move from the periphery of the spool core into a cut-out in the spool core to engage with the spool core when the spool core is rotated relative to the flange in the unwinding direction and to allow the locking pawl to move out of the cut-out to disengage the spool core when the spool core is rotated relative to the flange in the winding direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

Reference is made to commonly assigned copending applications Ser. No.07/787,356, entitled FILM CASSETTE WITH INTEGRATED CASSETTE ELEMENT LOCKAND LIGHT BLOCKING DEVICE and filed Nov. 4, 1991 in the name of DennisR. Zander and Ser. No. 07/787,802, entitled FILM CASSETTE WITH UNITARYFILM STRIPPER AND LIGHT BLOCKING DEVICE and filed Nov. 4, 1991 in thename of Dennis R. Zander.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to the field of photography, and inparticular to a film cassette containing roll film.

2. Description of the Prior Art

Commonly assigned U.S. Pat. No. 5,031,852, issued Jul. 16, 1991discloses a film cassette wherein a film spool comprises a spool coresupported for rotation in an unwinding direction to thrust a leadersection of a film roll coiled about the spool core to the exterior ofthe cassette and in a winding direction to return the film leader to theinterior of the cassette, and a pair of flanges positioned along thespool core to overlie opposite sides of the film roll to radiallyconfine the film roll within skirted peripheries of the flanges. Theflanges have respective central openings through which the spool corecoaxially extends to normally permit the flanges and the spool core tobe independently rotated in the two directions. According to theinvention, hooks are rotatably fixed to the spool core for initialrotation with the spool core relative to the flanges in the unwindingdirection, for movement into engagement holes in at least one of theflanges to make the flange rotate in unity with the spool core when thespool core is rotated further in the unwinding direction, to improve theability of the film spool to thrust the film leader from the cassette,and in the film winding direction, for movement out of the engagementholes in the flange to permit the flange to be independently rotatedwhen the spool core is rotated further in the winding direction, tosubstantially ensure the film leader can be rewound within the skirtedperiphery of the flange.

It has been found that by fixing at least one of the flanges to thespool core during unwinding rotation of the spool core, as contrastedwith allowing each of the flanges to remain rotatable independently ofthe spool core as in commonly assigned U.S. Pat. No. 4,834,306 and U.S.Pat. No. 4,848,693, there is immediately effected a frictionalrelationship between the outermost convolution of the film roll and theskirted periphery of the fixed flange which improves the ability of thefilm spool to thrust the film leader to the exterior of the cassette. Inparticular, the frictional relationship increases the pushing force thefilm spool applies to the film leader to propel the leader out of thecassette. Moreover, it has been found that by allowing both of theflanges to be rotated independently of the spool core during windingrotation of the spool core, as in commonly assigned U.S. Pat. Nos.4,834,306 and 4,848,693, it is substantially ensured that the filmleader will be rewound within the skirted peripheries of the flangeswithout being obstructed by the skirted peripheries.

SUMMARY OF THE INVENTION

According to the invention, there is provided an improved film cassettewherein a flange has a central opening into which a spool core extendsto allow rotation of the spool core relative to the flange in filmunwinding and film winding directions, and respective engagement meansare located on the flange and the spool core for engaging the flangewith the spool core responsive to rotation of the spool core relative tothe flange in the unwinding direction to make the flange rotate with thespool core in the unwinding direction to advance a filmstrip off thespool core and for disengaging the flange and the spool core responsiveto rotation of the spool core relative to the flange in the windingdirection to allow the spool core to rotate independently of the flangein the winding direction to wind a filmstrip onto the spool core, andwherein the improvement comprises:

said engagement means located on the spool core is defined by a cut-outin the periphery of the spool core within the central opening in theflange; and

said engagement means located on the flange is a locking pawl supportedon a resilient cantilever of the flange which biases the locking pawlinto the central opening to move from the periphery of the spool coreinto the cut-out to engage with the spool core when the spool core isrotated relative to the flange in the unwinding direction and to allowthe locking pawl to move out of the cut-out to disengage the spool corewhen the spool core is rotated relative to the flange in the windingdirection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a film cassette according to apreferred embodiment of the invention, showing two halves of thecassette shell opened and the various cassette components removed fromthe shell halves;

FIG. 2 is a perspective view of the film cassette, showing the two shelfhalves opened with the various cassette components in place;

FIG. 3 is a perspective of the film cassette partly cut away;

FIG. 4 is an elevation view in cross-section of the film cassette;

FIG. 5 is a plan view in cross-section of a flange to spool coreengagement in the film cassette; and

FIGS. 6-14 are either plan views in cross-section or end views of thefilm cassette, showing operation of a unified light valve, film stripperand spool lock.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention is disclosed as being embodied preferably in a 35 mm filmcassette. Because the features of this type of film cassette aregenerally known, the description which follows is directed in particularto elements forming part of or cooperating directly with the disclosedembodiment. It is to be understood, however, that other elements notspecifically shown or described may take various forms known to personsof ordinary skill in the art.

The Film Cassette--General

Referring now to the drawings, FIGS. 1 and 2 show a 35 mm film cassette1 comprising a cassette shell and a film spool 5. The film spool 5 isrotatable about an axis X in film unwinding and film winding directionsU and W inside the cassette shell 3. The cassette shell 3 consists oftwo shell halves 7 and 9 which are connected by a pair of spaced,integrally formed hinges 11 and 13 and otherwise are secured together byknown means.

A roll 15 of 35 mm filmstrip F is coiled about a core or hub 17 of thefilm spool 5 to form successive convolutions of the filmstrip. As shownin FIGS. 4 and 8, the film roll 15 includes an outermost convolutionwhich is a film leader 19 having a leading or forward inclined end 21,and it includes a next inward convolution 23 coiled beneath theoutermost convolution. An inner or trailing end of an innermostconvolution 24 of the film roll 15 is secured to the spool core 17 byappropriate means such as a hook or tape, not shown.

Adjacent one end 25 of the spool core 17, a pair of parallel inner andouter rigid disks 27 and 29 are integrally formed with the spool core.Both of the disks 27 and 29 are arranged perpendicular to the axis X.See FIGS. 1-4. Adjacent another end 31 of the spool core 17, a rigidflange 33 is supported inclined to the axis X by four disk guides 35, 37and 39, only three shown, projecting from an inner wall 41 of the shellhalf 7. Other disk guides, not shown, project from an inner wall 42 ofthe shell half 9. The flange 33 has a central opening 43 through whichthe spool core 17 extends to allow rotation of the spool coreindependently of the flange, and it includes an annular lip or skirt 45which circumferentially extends from the flange. As shown in FIGS. 1 and4, the inner disk 29 and the flange's annular lip 45 are spaced fromeach other a distance that is less than the width W of the filmstrip Ffor an approximately 270° arc that is remote from a film egress/ingresspassageway 47 to outside the cassette shell 3, to radially confine thefilm leader 19 to the film roll 15 along that arc in order tosubstantially prevent clock-springing of the film roll against therespective inner walls 41, 42 of the shell halves 7, 9. Conversely, theinner disk 29 and the flange's annular lip 45 are spaced from each othera distance that is greater than the width W of the filmstrip F for anapproximately 90° arc that is close to the passageway 47, to allow thefilm leader 19 beginning with its leading end 21 to escape the radialconfinement of the flange's annular lip along that arc in order to enterthe passageway. A functionally similar arrangement is disclosed incommonly assigned U.S. Pat. No. 4,832,275, issued May 23, 1989.

Flange To Spool Core Engagement

The flange 33 includes an integrally formed resilient cantilever 48bordered by a pair of longitudinal slits or openings 49 and 50 cut inthe flange to interconnect at a common opening 51 to the central opening43 of the flange. See FIG. 5. The cantilever 48 has a free end portionat the common opening 51 which defines a locking pawl 52 that isinherently biased against the periphery of the spool core 17 at alocation within the central opening 43, to drop into either one of twoidentical notches or detents 53 and 54 cut in the periphery of the spoolcore. When the locking pawl 52 rests against the periphery of the spoolcore 17, the cantilever 48 occupies the longitudinal slit 49. When thelocking pawl 52 is in one of the detents 53, 54, it is removed from thelongitudinal slit 49. The locking pawl 52 and the detents 53, 54 arecomplementarily shaped to locking engage the pawl and one of the detentswhen the spool core 17 is rotated relative to the flange 33 in theunwinding direction U. Once the locking pawl 52 and one of the detents53, 54 are lockingly engaged, the flange 33 must rotate with the spoolcore 17 in the unwinding direction. Conversely, the locking pawl 52 andthe detents 53, 54 are complementarily shaped to disengage the pawl andone of the detents and force the pawl onto the periphery of the spoolcore 17 when the spool core is rotated relative to the flange 33 in thewinding direction W. Another type of flange to spool core engagementarrangement is disclosed in commonly assigned U.S. Pat. No. 5,031,852,issued Jul. 16, 1991.

Unitary Film Stripper, Spool Lock and Light Valve

A control shaft 55 has an integrally formed light valve 57, filmstripper 59 and spool lock 61. See FIGS. 1-4. The stripper 59 comprisesthe free end of a resilient cantilever 63 extending from the controlshaft 55.

The control shaft 55 is rotatably supported within the cassette shell 3by the shell halves 7 and 9. See FIGS. 1-3. Opposite ends 64 and 65 ofthe control shaft 55 are accessible at the exterior of the cassetteshell 3 for engagement to rotate the control shaft.

As shown in FIG. 6, when the control shaft 55 is rotationally orientedwith the light valve 57 in a light blocking or closed position extendingacross the film egress/ingress passageway 47 to prevent ambient lightfrom entering the cassette shell 3 through the passageway, the filmstripper 59 is in a non-stripping position removed from the film roll15. Conversely, as shown in FIG. 8, when the control shaft 55 isrotationally oriented with the light valve in a non-blocking or openedposition to allow movement of the filmstrip F through the passageway 47,the stripper 59 is in a stripping position to be received between theleading end 21 of the film leader 19 and the next-inward convolution 23of the film roll 15 responsive to rotation of the film spool 5 in theunwinding direction U. Other details of the stripper 59 are disclosed incross-referenced application Ser. No. 07/787,356. If the film spool 5 isrotated in the unwinding direction U with the stripper 59 in itsstripping position, the film leader 19 beginning with the leading end 21will be guided by the stripper from between the flange's annular lip 33and the inner disk 29 into the passageway 47. A protruberance 67 may beprovided on the underside of the film leader 19 at a location proximatethe leading film end 21 to normally lie against the outerside of thenext-inward film convolution 23, to maintain a slight space between theleading film end and the next-inward film convolution for receipt of thestripper 59. See FIG. 8.

As shown in FIGS. 2 and 8, when the control shaft 55 is rotationallyoriented with the light valve 57 in its non-blocking position, the spoollock 61 is in a non-locking position removed from the inner disk 29.Conversely, as shown in FIG. 6, when the control shaft 55 isrotationally oriented with the light valve 57 in its light blockingposition, the spool lock 61 is in a locking position protruding into anyone of four notches or detents 69, 71, 73 and 75 cut in the periphery ofthe inner disk 29, to prevent substantial rotation of the film spool 5in the unwinding and winding directions U and W. Other details of thespool lock 61 are disclosed in cross-referenced application Ser. No.07/787,356. When the spool lock 61 protrudes into the detent 69, thefilm spool 5 is rotationally arrested with a film exposure statusindicator 77 completely filling a window 79 in one end 81 of the shellhalf 7, to visibly indicate the filmstrip F is unexposed (fresh). SeeFIGS. 6 and 7. Moreover, a beveled edge portion 83 of the outer disk 27is present at two windows 85 and 87 in the end 89 of the shell half 9,to disable a cassette load prevention mechanism in a camera or otherapparatus adapted to receive the film cassette 1. See FIG. 7. An exampleof the cassette load prevention mechanism is disclosed in commonlyassigned U.S. Pat. Nos. 5,032,861, issued Jul. 16, 1991, and 5,047,794,issued Sep. 10, 1991. When the spool lock 61 protrudes into the detent71, the film spool 5 is rotationally arrested with the exposure statusindicator 77 only partly filling the window 79 to visibly indicate thefilmstrip F is partly exposed. See FIGS. 9 and 10. Moreover, the bevelededge portion 83 is only present at the window 85. A cut-out edge portion91 of the outer disk 27 is present at the window 87. See FIG. 10.Consequently, the cassette load prevention mechanism would be disabledat the window 87 but not at the window 85. This permits the filmcassette 1 to be used with two different types of cameras, one that canreceive the film cassette with the filmstrip F either partly exposed orunexposed and the other that can receive the film cassette only with thefilmstrip unexposed. When the spool lock 61 protrudes into the detent73, the film spool 5 is rotationally arrested with the exposure statusindicator 77 completely removed from the window 79 to visibly indicatethe filmstrip F is fully exposed. See FIGS. 11 and 12. Moreover, thecut-out edge portion 91 is present at the windows 85 and 87. See FIG.12. Consequently, the cassette load prevention mechanism would bedisabled at the windows 85 and 87. This is in order to prevent any typecamera from receiving the film cassette 1 with the filmstrip F fullyexposed. When the spool lock 61 protrudes into the detent 75, the filmspool 5 is rotationally arrested with the exposure status indicator 77completely removed from the window 79. However, another indicator, notshown, may be provided on the outer disk 27 to be present at the window79 to visibly indicate the filmstrip F has been processed to develop anylatent images. See FIGS. 13 and 14. Moreover, the cut-out edge portion91 is present at the window 85 and the beveled edge portion 83 ispresent at the window 87. See FIG. 14. Consequently, the cassette loadprevention mechanism would be disabled at the window 85 but not thewindow 87. This is in order to allow the film cassette 1 only to bereceived in apparatus other than a camera, such as an image displaydevice, which would make use of the filmstrip F when it is processed.

Operation

Initially, the control shaft 55 must be rotated to move the light valve57 from its light blocking position to its non-blocking position, tomove the spool lock 61 from its locking position to its nonlockingposition, and to move the film stripper 59 from its non-strippingposition to its stripping position. See FIGS. 6 and 7.

Then, the spool core 17 is rotated relative to the flange 33 in theunwinding direction U until the two pieces are lockingly engaged bymeans of the locking pawl 52 and one of the detents 53, 54. See FIG. 5.Continued rotation of the spool core 17 in the same direction willsimilarly rotate the flange 33 to allow successive longitudinallysections of the filmstrip F beginning with its leading end 21 to exitfrom between the flange's annular lip 45 and the inner disc 29 along the90° arc close to the film egress/ingress passageway 47 where the lip andthe disc are spaced from each other a distance that is greater than thewidth W of the filmstrip F. Simultaneously, the film stripper 59 willdirect successive longitudinal sections of the filmstrip F beginningwith its leading end 21 into the passageway 47 for advancement outsidethe cassette shell 3.

The invention has been described with reference to a preferredembodiment. However, it will be appreciated that variations andmodifications can be effected within the ordinary skill in the artwithout departing from the scope of the invention.

I claim:
 1. A film cassette wherein a flange has a central opening intowhich a spool core extends to allow rotation of said spool core relativeto said flange in film unwinding and film winding directions, andrespective engagement means are located on said flange and said spoolcore for engaging the flange with the spool core responsive to rotationof the spool core relative to the flange in the unwinding direction tothen make the flange rotate with the spool core in the unwindingdirection to advance a filmstrip off the spool and for disengaging theflange and the spool core responsive to rotation of the spool corerelative to the flange in the winding direction to allow the spool coreto rotate independently of the flange in the winding direction to wind afilmstrip onto the spool core, and wherein the improvementcomprises:said engagement means located on said spool core is defined bya cut-out in the periphery of the spool core within said central openingin said flange; and said engagement means located on said flange is alocking pawl supported on a resilient cantilever of the flange whichbiases said locking pawl into said central opening to move from theperiphery of said spool core into said cut-out to engage with the spoolcore when the spool core is rotated relative to the flange in theunwinding direction and to allow the locking pawl to move out of thecut-out to disengage the spool core when the spool core is rotatedrelative to the flange in the winding direction.
 2. The improvement asrecited in claim 1, wherein locking pawl and said cutout arecomplementarily shaped to force the locking pawl out of the cut-out andonto the periphery of said spool core when the spool core is rotatedrelative to said flange in the winding direction.
 3. The improvement asrecited in claim 2, wherein said flange has a longitudinal opening atleast coextensive with said cantilever to receive the cantilevertransversely when said locking pawl is forced out of said cut-out andonto the periphery of said spool core.